Early in his reign, Beopheung had desired to promulgate Buddhism as the state religion. However, officials in his court opposed him. In the fourteenth year of his reign, Beopheung's "Grand Secretary", Ichadon, devised a strategy to overcome court opposition. Ichadon schemed with the king, convincing him to make a proclamation granting Buddhism official state sanction using the royal seal. Ichadon told the king to deny having made such a proclamation when the opposing officials received it and demanded an explanation. Instead, Ichadon would confess and accept the punishment of execution, for what would quickly be seen as a forgery.
Ichadon prophesied to the king that at his execution a wonderful miracle would convince the opposing court faction of Buddhism's power. Ichadon's scheme went as planned, and the opposing officials took the bait. When Ichadon was executed on the 15th day of the 9th month in 527, his prophecy was fulfilled; the earth shook, the sun was darkened, beautiful flowers rained from the sky, his severed head flew to the sacred Geumgang mountains, and milk instead of blood sprayed 100 feet in the air from his beheaded corpse. The omen was accepted by the opposing court officials as a manifestation of heaven's approval, and Buddhism was made the state religion in 527 CE. Ichadon's body was then taken to the Geumgang mountains and buried there with respect. His martyrdom led to the construction of Heungryun monastery, Silla's first state-sponsored temple.